1. Field of the Invention
The invention relates in general to a carrier frequency offset (CFO) compensation apparatus and associated method, and more particularly to carrier frequency offset compensation apparatus and associated method for a wireless communication system.
2. Description of the Related Art
In a wireless communication system, a transmission end modulates a signal to be transmitted, up-converts the modulated signal to a radio-frequency (RF) signal, and transmits the RF signal. A reception end receives the RF signal via an antenna, down-converts the RF signal to a baseband signal, and demodulates the baseband signal. Due to a difference between an oscillation frequency for up-conversion at the transmission end and an oscillation frequency for down-conversion at the reception end, an issue of carrier frequency offset in the down-converted signal at the reception end is caused. Such issue adds complications to the demodulation process and also results in an increased transmission bit error rate of the wireless communication system.
Therefore, a wireless communication system usually includes a carrier frequency offset estimation and compensation apparatus for solving the carrier frequency offset. For example, the US Patent Publication 2011/0188611 A1 discloses “Signal Processing Circuit and Method Thereof”, the US Patent Publication 2010/0296002 A1 discloses “Circuit for Detecting a Digital Data Stream and Associated Method”, and the US Patent Publication 2011/0002422 A1 discloses “Apparatus for Detecting Digital Video Signal Parameters and Method Thereof”. However, in certain communication systems, e.g., a Digital Video Broadcasting-Satellite (DVB-S) communication system, the carrier frequency offset is more severe compared to other communication systems. More particularly, with a low signal-to-noise ratio (SNR), the carrier frequency offset can be aggravated. Therefore, there is a need for a solution for solving the above issue.